For some time, use of aerosol spray systems have been utilized to provide easy, rapid delivery of hair-fixing compositions to the surface of the hair. Ordinarily, such systems consist of a single-phase which comprises a solvent (usually an alcohol) which is capable of dissolving both the hair-fixing composition and the aerosol propellant (which is usually a hydrocarbon or a halogenated hydrocarbon having a high vapor pressure). These single-phase systems deliver a fairly uniform amount of composition in the spray until the contents of the container are exhausted.
However, the environmental consciousness of the international community is increasing the use of such propellants is becoming much less desirable. Additionally, the popularity of alcohol in hairsprays is declining among the consumer population due to the perception that it dries out the hair, making it brittle and easily damaged.
Because of these and other reasons, researchers have attempted to utilize water as the sole solvent in aerosol hairsprays. For example, U.S. Pat. No. 3,207,386 discloses a single-phase aqueous system which utilizes dimethyl ether as the propellant. However, this system suffers from the distinct drawback of requiring the amounts of resin, water, and propellant to fall within narrow limits of solubility to form a usable spray.
Use of a two-phase (solvent and propellant) system was disclosed in U.S. Pat. No. 3,137,416, wherein the propellant is used to force an aqueous or water/alcohol solution of hairspray resin through a dip tube to form the spray, resulting in a very wet spray. This system suffers from the drawback of having to use a large quantity of propellant, as well as the fact that only water (or water/alcohol) soluble resins can be used. Also, according to the patent, mixing of the propellant and aqueous phases is to be avoided; thus, the containers must be handled very carefully prior to use.
A number of researchers have also attempted to make single-phase aqueous systems by including organic cosolvents with the water. These cosolvents, which are usually alcohols, are often employed in very large amounts, generally exceeding 30%, making them a substantial component in the hairspray systems. It follows that these systems suffer from the same drawbacks as alcohol or organic solvent systems.
Thus, there exists a real need for aqueous based-systems which exhibit a wide versatility with regard to resins which can be used, relative proportions of each component, and lack the requirement of an organic cosolvent.